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to choose at one's own discretion
to choose when to do something; to estimate (the time for something)
お客の好みを見計らって料理を出すのがプロだ。
A professional serves dishes based on the customer's preferences.
上司がいないタイミングを見計らって休憩した。
I took a break at a time when my boss was not around.
相手の隙を見計らって攻撃を仕掛けた。
He launched an attack after gauging the opponent's opening.